A conventional pick and place robot is typically provided with a vacuum spindle. For example, U.S. Pat. No. 4,135,630, the entire contents of which is hereby expressly incorporated by reference, describes a vacuum spindle with a tubular vacuum nozzle. U.S. Pat. No. 4,838,452, the entire contents of which is hereby expressly incorporated by reference, describes a vacuum spindle with a vacuum nozzle having an cylindrically expanded lower surface. U.S. Pat. No. 5,105,528, the entire contents of which is hereby expressly incorporated by reference, describes apparatus for automatically interchanging vacuum nozzles on a vacuum spindle. U.S. Pat. No. 5,201,696, the entire contents of which is hereby expressly incorporated by reference, describes apparatus for automatically interchanging vacuum nozzles on a vacuum spindle with vacuum seals located between the vacuum spindle and the interchangeable nozzles. U.S. Pat. No. 5,285,888, the entire contents of which is hereby expressly incorporated by reference, describes apparatus for the control of the movement of a vacuum nozzle. U.S. Pat. No. 5,285,946, the entire contents of which is hereby expressly incorporated by reference, describes a vacuum nozzle having a strain gauge.
A suction cup or O-ring type of compliant rubber substance is conventionally provided on the bottom of the nozzle to help hold a part by vacuum that is to be placed on a circuit board during a pick and place process. A problem with these compliant devices is undesirable lifting or shifting of the part in relation to the circuit board after it has been placed on the circuit board. This disadvantageous lifting or shifting of the placed part can happen when the compliant material on the nozzle tip is of a low durometer hardness. On the other hand, a low durometer hardness nozzle tip is desirable in order to be able to pick parts out of a feeder by vacuum when the top surface of the parts are not parallel to the bottom surface of the tip or having a rough or uneven top surface.
Previously, it was attempted to solve this problem by providing an air kiss over-pressure on the top of the component while simultaneously removing the nozzle slowly away from the component. The disadvantage with this approach is that it slows down the production rate of the machine and the air kiss itself may cause shifting of components.